The Hranicka Abyss is at least 1,325 feet deep, and likely goes down further. — -- A team of explorers believe they have discovered the deepest known underwater cavern the world in eastern Czech ...

Forbes contributors publish independent expert analyses and insights. I write about biodiversity and the hidden quirks of the natural world.

June 15, 2006 — -- "Nightline" joined forces with writer Tim Zimmerman and filmmaker Gordon Hiles, who documented an ambitious dive to one of the world's deepest, most dangerous underwater caves.

This incredible submerged cave network is the longest of its kind in the world and plays a vital role in the region.